I recommend preparing to work in a professional 3D modeling environment.

If you want to create models or work in an industry related more to solid modeling, I would aim to become a Solidworks or Catia modeler.
Free step-in environments are 123D Design or Freecad. They work in a similar way as Solidworks though much more limited.

If you're looking to be a Mesh modeler, say in Cinema4D or 3D Studio Max, Blender is a nice free program.

For free sculpting I use Sculptris.

Then there's NURBS modeling such as in Rhino or Alias. Rhino is a very good 3D CAD package with a price affordable to small business owners. They have a free 90-day fully functioning trial.